my question concerns the level of mods to the engine to warrant a upgrade in octane levels. untill my warranty runs out i dont think i will go much far past maybe a short ram(password jdm carbon fiber sexyness!!) and maybe a cat-back exhaust(j's racing Ti exhaust!!) do i need to go up from 87 to 89 or do i need to throw on the premium? any help please. thanks and im looking to be a Fit owner soon!!!

 

you dont have to upgrade with those mods.

i mean...really you dont have to put it untill you actually boost!

i think....


i pour 91 regardless. i can feel the difference.

 

Contrary to popular belief, high-octane gas is not more powerful than regular gas. Higher octane gas is simply more difficult to ignite. If you use lower octane gas in a higher compression engine, you run the risk of pre-detonation. This means that the fuel will ignite not from the spark plug, but from the heat caused when the piston compresses the air/fuel mixture. This can cause great harm to the engine. Higher octane gas will not pre-detonate under this higher compression. This also means that using premium fuel in an engine not designed for it will not offer any performance advantage over regular grade. It will not make your car faster. All it will do is lighten your wallet faster.

 

you won't need to run higher octane fuel until you mess with the computer. higher octane fuel doesn't give you better fuel economy or performance in your car.

 

only if you are adding a form of forced induction (supercharger, Turbo, Nitrous) or if you are increasing the compression of your engine. also most likely with a ca swap(not available) and ecu upgrade.

 

thanks for the rapid response. im going to look at a fit sport today. wish me luck!!

 

see thats what i dont get. we have an eco car.

that has a pretty high compression 10:4:1?

 

yeah we have pretty high combustion already because the engine is so small. to answer your question perfor.element, you only need to use higher octane if you supercharge or turbocharge your engine.

 

What Doom says is correct. Another old hot rod trick to raise compression is to remove the head, take it to a machine shop and have it shaved. The only way to raise compression is to add boost, shave the head, or replace the pistons. The computer has nothing to do with compression.

 

Everyone is correct. NA bolt on parts dont require an octane bump. However, when installing an aftermarket header and downpipe (cat-delete/testpipe) along with a full exhaust the Fit is known to run higher AFR's.

At around 13.5 AFR's the Fit stops making power. Some companies have noticed with a header, downpipe, and cat-back the Fit runs higher AFR's. Its fine on the motor but the power gains basically stop.

A tune can help this. Not higher octane.

 

I have yet to put in 91 in my take. It's been something like 13,000 miles and I still haven't. But now that you said that, I think I'll spend a little more my next tank to see if i can feel the difference.

 

yea im thinking a few mods not a whole lot. need to make a bit more dough before i look for boost. im looking forward to more options coming out for the fit. tommmrow im off to look at a few more fits. black or red. decisions, decisions!! wish me luck.